From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3rYrRB6DBQzDq5c for ; Wed, 22 Jun 2016 00:56:54 +1000 (AEST) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u5LErke2139637 for ; Tue, 21 Jun 2016 10:56:52 -0400 Received: from e23smtp04.au.ibm.com (e23smtp04.au.ibm.com [202.81.31.146]) by mx0a-001b2d01.pphosted.com with ESMTP id 23q794h9y8-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 21 Jun 2016 10:56:52 -0400 Received: from localhost by e23smtp04.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 22 Jun 2016 00:56:49 +1000 Received: from d23relay08.au.ibm.com (d23relay08.au.ibm.com [9.185.71.33]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id AD0B22CE8054 for ; Wed, 22 Jun 2016 00:56:46 +1000 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay08.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u5LEuk7w6553944 for ; Wed, 22 Jun 2016 00:56:46 +1000 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u5LEujEv001838 for ; Wed, 22 Jun 2016 00:56:46 +1000 From: Madhavan Srinivasan To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: Madhavan Srinivasan , Yury Norov , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Adrian Hunter , Kan Liang , Wang Nan , Michael Ellerman Subject: [PATCH v3] tools/perf: Fix the mask in regs_dump__printf and print_sample_iregs Date: Tue, 21 Jun 2016 20:26:40 +0530 Message-Id: <1466521000-11329-1-git-send-email-maddy@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , When decoding the perf_regs mask in regs_dump__printf(), we loop through the mask using find_first_bit and find_next_bit functions. "mask" is of type "u64", but sent as a "unsigned long *" to lib functions along with sizeof(). While the exisitng code works fine in most of the case, the logic is broken when using a 32bit perf on a 64bit kernel (Big Endian). When reading u64 using (u32 *)(&val)[0], perf (lib/find_*_bit()) assumes it gets lower 32bits of u64 which is wrong. Proposed fix is to swap the words of the u64 to handle this case. This is _not_ endianess swap. Suggested-by: Yury Norov Cc: Yury Norov Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Adrian Hunter Cc: Kan Liang Cc: Wang Nan Cc: Michael Ellerman Signed-off-by: Madhavan Srinivasan --- Changelog v2: 1)Moved the swap code to a common function 2)Added more comments in the code Changelog v1: 1)updated commit message and patch subject 2)Add the fix to print_sample_iregs() in builtin-script.c tools/include/linux/bitmap.h | 9 +++++++++ tools/perf/builtin-script.c | 16 +++++++++++++++- tools/perf/util/session.c | 16 +++++++++++++++- 3 files changed, 39 insertions(+), 2 deletions(-) diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h index 28f5493da491..79998b26eb04 100644 --- a/tools/include/linux/bitmap.h +++ b/tools/include/linux/bitmap.h @@ -2,6 +2,7 @@ #define _PERF_BITOPS_H #include +#include #include #define DECLARE_BITMAP(name,bits) \ @@ -22,6 +23,14 @@ void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, #define small_const_nbits(nbits) \ (__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG) +static inline void bitmap_from_u64(unsigned long *_mask, u64 mask) +{ + _mask[0] = mask & ULONG_MAX; + + if (sizeof(mask) > sizeof(unsigned long)) + _mask[1] = mask >> 32; +} + static inline void bitmap_zero(unsigned long *dst, int nbits) { if (small_const_nbits(nbits)) diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index e3ce2f34d3ad..73928310fd91 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -412,11 +412,25 @@ static void print_sample_iregs(struct perf_sample *sample, struct regs_dump *regs = &sample->intr_regs; uint64_t mask = attr->sample_regs_intr; unsigned i = 0, r; + unsigned long _mask[sizeof(mask)/sizeof(unsigned long)]; if (!regs) return; - for_each_set_bit(r, (unsigned long *) &mask, sizeof(mask) * 8) { + /* + * Since u64 is passed as 'unsigned long *', check + * to see whether we need to swap words within u64. + * Reason being, in 32 bit big endian userspace on a + * 64bit kernel, 'unsigned long' is 32 bits. + * When reading u64 using (u32 *)(&val)[0] and (u32 *)(&val)[1], + * we will get wrong value for the mask. This is what + * find_first_bit() and find_next_bit() is doing. + * Issue here is "(u32 *)(&val)[0]" gets upper 32 bits of u64, + * but perf assumes it gets lower 32bits of u64. Hence the check + * and swap. + */ + bitmap_from_u64(_mask, mask); + for_each_set_bit(r, _mask, sizeof(mask) * 8) { u64 val = regs->regs[i++]; printf("%5s:0x%"PRIx64" ", perf_reg_name(r), val); } diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 5214974e841a..1337b1c73f82 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -940,8 +940,22 @@ static void branch_stack__printf(struct perf_sample *sample) static void regs_dump__printf(u64 mask, u64 *regs) { unsigned rid, i = 0; + unsigned long _mask[sizeof(mask)/sizeof(unsigned long)]; - for_each_set_bit(rid, (unsigned long *) &mask, sizeof(mask) * 8) { + /* + * Since u64 is passed as 'unsigned long *', check + * to see whether we need to swap words within u64. + * Reason being, in 32 bit big endian userspace on a + * 64bit kernel, 'unsigned long' is 32 bits. + * When reading u64 using (u32 *)(&val)[0] and (u32 *)(&val)[1], + * we will get wrong value for the mask. This is what + * find_first_bit() and find_next_bit() is doing. + * Issue here is "(u32 *)(&val)[0]" gets upper 32 bits of u64, + * but perf assumes it gets lower 32bits of u64. Hence the check + * and swap. + */ + bitmap_from_u64(_mask, mask); + for_each_set_bit(rid, _mask, sizeof(mask) * 8) { u64 val = regs[i++]; printf(".... %-5s 0x%" PRIx64 "\n", -- 1.9.1